Unravelling the History of the Lunar Regolith

Abstract

The lunar regolith is sensitive to the bombardment history of the Moon and contains a wealth of knowledge regarding the types of processes that have modified the lunar crust through time. Noble gases that are produced and trapped in the lunar regolith, as a result of this interaction with the space environment, can be used to determine the cosmic ray exposure age, maturity, shielding depth and antiquity age of lunar regolith samples. This thesis aims to probe this temporal archive to further understand the impact history of the Moon contained within the regolith.Initially, all the published noble gas literature data for the Apollo regolith breccias, drill cores and soils was compiled into a database where trapped and cosmogenic noble gas component were calculated. These data were used to summarise the history of the lunar regolith contained in the Apollo sample archive. A dichotomy between the "ancient" (determined by the antiquity indicator using the 40Ar/36Artr ratio) regolith samples and those formed in more recent times has been described previously (e.g., McKay et al., 1986).The ancient breccias and soils (>~3.5 Ga) have typically experienced limited amounts of surface exposure (i.e., they are 'immature'). Whereas, regolith samples formed in more recent times (

Date of Award	1 Aug 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Raymond Burgess (Supervisor) & Katherine Joy (Supervisor)